1. Field of the Invention
The present invention relates to a 2-pyridylacetic acid having the formula (I): ##STR2## wherein R.sup.1 represents an alkyl having 5 to 10 carbon atom or --(CH.sub.2).sub.m -cycloalkyl group having C.sub.5 -C.sub.8 cycloalkyl, which may be substituted with at least one alkyl group having 1 to 6 carbon atoms, where m represents zero or an integer of 1 to 4; R.sup.2 represents hydrogen, a linear alkyl preferably having 1 to 10 carbon atoms, a hydroxyalkyl preferably having 2 to 6 carbon atoms, an alkenyl preferably having 3 to 6 carbon atoms, an aryl preferably having 6 to 10 carbon atoms, an aralkyl preferably having 7 to 15 carbon atoms or a group--(CH.sub.2).sub.n --a, where n represents an integer of 0 to 3 and A represents a nitrogen-containing heterocyclic group which may be substituted with an alkyl having 1 to 10 carbon atoms or an aralkyl having 7 to 10 carbon atoms, a process for preparation thereof and a pharmaceutical composition or agent containing the same. More specifically, the 2-pyridylacetic acid derivatives and its pharmaceutically acceptable acid addition salts are novel compounds useful as therapeutical agents for peptic ulcers, since they have the effect of inhibiting attacking factors of peptic ulcer and the effect of potentiating defending factors and also have a low toxicity.
2. Description of the Related Art
The etiology of peptic ulcer has been discussed in terms of an imbalance between aggressive and defensive factors, but the factors which increase the resistance of tissue have not yet been clarified. Accordingly, the maximum to "no acid, no ulcer" remains still true, and under the present situation, the therapy target of peptic ulcers is still directed to a control of gastric acid.
In the recent years, potent inhibitors of gastric acid secretion such as histamine H.sub.2 receptor antagonist (cimetidine, ranitidine, famotidine) and antichlorinergics of gastric acid (pirenzepine) were introduced to therapeutics of gastric and duodenal ulcer patients. However, there are not sufficient for preventing a worsening or recurrence of an ulcer.
As mentioned above, a satisfactory effect cannot be obtained in the therapy of an ulcer only by the use of a drug which can prevent the generation of an ulcer, i.e., inhibit aggressive factors. Accordingly, under the present situation, a drug inhibiting aggressive factors and a protective drug for gastric mucosa are respectively selected or used in combinations of both types as the ulcer therapeutical agent, depending on the conditions of the disease. Although some compounds stated to have both such effects have been proposed, in practice these proved to have a weak inhibiting acid secretion, and to primarily have a protective effect for gastric mucosa.